Closure system with improved sealing of lid

ABSTRACT

A closure system is provided with a peripheral wall (e.g., as defined either by a top portion of a container for extending from, and defining, an opening or as defined by a separate closure body for extending from a container). The peripheral wall has a laterally inwardly extending sealing member. A lid is provided for being moved from an open position to a closed position on the peripheral wall. The lid has a flange with a peripheral sealable surface for being engaged by the sealing member of the peripheral wall to effect a seal.

CROSS-REFERENCE TO RELATED APPLICATION(S)

Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO A MICROFICHE APPENDIX

Not applicable.

TECHNICAL FIELD

This invention relates to a closure system for a container.

BACKGROUND OF THE INVENTION AND TECHNICAL PROBLEMS POSED BY THE PRIOR ART

There are a variety of types of conventional closures. One type of prior art closure system includes a body for being attached to the top of a container. The body defines an opening to the container interior. The system further includes a lid which is hingedly mounted on the body and which can be lifted up to expose the opening to the container interior. The closure body to which the lid is attached may be alternatively described as the closure base or base portion.

For some types of products, it would be desirable to provide a closure with a hinged top or other lid structure that could provide access to the product (such as fluent products, as well as non-fluent products), and that would optionally accommodate either the insertion of a utensil through the open closure to permit the product to be scooped out of the container with a spoon, knife, ladle, etc., or accommodate the insertion of a user's hand through the open closure so that the product can be lifted out by the user's hand.

It would be advantageous if such a closure could be provided with an improved seal between the lid and the closure body—especially for a “wide mouth” closure in which the smallest dimension across the product discharge opening is at least 40 mm. or more. In the past, the inventors of the present invention have found that it is difficult to design wide mouth, disposable, thermoplastic closures that have sufficiently good sealing capabilities and that are sufficiently robust to accommodate manufacturing processes, assembly processes, and handling during shipping and use.

It would be desirable to provide an improved seal for a closure, including a wide mouth closure, in which the seal could function effectively to provide proper sealing and that would be sufficiently robust. It would be also especially desirable if such an improved seal could function effectively to guide a cooperating portion of the lid during closing of the lid.

It would also be beneficial if the improved seal could accommodate some warpage or other distortion of a large closure without deleteriously affecting the sealing capability.

Further, it would also be desirable if the improved seal had the optional capability for being incorporated in a closure having a lid that could be preferably connected with a hinge to the closure body.

It would also be advantageous if a closure with such an improved seal could accommodate containers which have a variety of shapes and which are constructed from a variety of materials.

Preferably, a closure with such an improved seal should accommodate ease of use. Preferably, the structural features of such an improved closure should also be capable of being readily incorporated into a design that facilitates cleaning of the closure.

It would also be beneficial if a closure with such an improved seal could readily accommodate its manufacture from a thermoplastic material.

It would also be desirable if a closure with such an improved seal could be molded from thermoplastic materials in one or more pieces, and preferably molded in only one, integral unit so as to not require assembly of multiple parts.

Further, it would be desirable if a closure with such an improved seal could accommodate efficient, high-quality, high-speed, large volume manufacturing techniques with a reduced product reject rate to produce products having consistent operating characteristics unit-to-unit with high reliability.

It would also be advantageous if such an improved seal could also optionally be incorporated, at least in part, directly in a container around the container opening to function as part of the closure system without requiring the use of a separate closure body, per se.

BRIEF SUMMARY OF THE INVENTION

The improved seal of the present invention can be incorporated into a closure system that may include one or more of the above-discussed, desired features.

According to one aspect of the present invention, a first form of such a closure system is provided for a container that has an interior where a product may be stored. The closure system includes:

-   -   (A) a peripheral wall for extending from the container around an         opening to the container interior and through which the product         can be removed in a discharge direction that is perpendicular to         the opening; and     -   (B) a lid that is movable between (1) a closed position         occluding the opening, and (2) a fully opened position exposing         the opening.

The peripheral wall may be a closure base formed as a unitary or integral extension of the container, or may be a separate closure body for installation on the container. The peripheral wall includes a laterally inwardly extending sealing member cantilevered over part of the opening. The sealing member includes a first portion and a distal second portion having a transverse cross-sectional configuration that is defined by (a) a laterally inwardly extending top arcuate surface, (b) a laterally inwardly extending bottom arcuate surface, and (c) a sealing surface that is generally parallel to the discharge direction and that extends between, and merges with, the top arcuate surface and the bottom arcuate surface.

The lid includes a closure flange that defines a peripheral sealable surface which, when the lid is in said closed position, is (a) oriented generally parallel to the discharge direction, and (b) sealingly engaged with the sealing surface of the distal second portion of the sealing member so as to force the distal second portion laterally outwardly.

According to another aspect of the invention, another form of a closure system is provided for a container that has an interior where a product may be stored, and the closure system includes:

-   -   (A) a peripheral wall for extending from the container around an         opening to the container interior and through which the product         can be removed in a discharge direction that is perpendicular to         the opening; and     -   (B) a lid movable between (1) a closed position occluding the         opening, and (2) a fully opened position exposing the opening;         and wherein         -   (a) the peripheral wall includes a laterally inwardly             extending sealing member cantilevered over part of the             opening, the sealing member including a first portion and a             distal second portion extending from the first portion to             define a sealing surface that is generally parallel to the             discharge direction; and         -   (b) the lid includes a closure flange that defines a             peripheral sealable surface which, when the lid is in the             closed position,             -   (i) is oriented generally parallel to the discharge                 direction,             -   (ii) has a minimum lateral dimension measured across the                 locus of the periphery defined by the sealable surface                 that exceeds 40 mm.;             -   (iii) is sealingly engaged with the sealing surface of                 the distal second portion of the sealing member of the                 peripheral wall so as to force the distal second portion                 laterally outwardly; and             -   (iv) extends inwardly, in the direction opposite to the                 discharge direction, beyond the peripheral wall sealing                 member by an amount that is between about 0.5% and about                 10.0% of the largest lateral dimension measured across                 the locus of the periphery defined by the lid flange                 sealable surface.

According to another aspect of the invention, another form of a closure system is provided for a container that has an interior where a product may be stored, and the closure system includes:

-   -   (A) a peripheral wall for extending from the container around an         opening to the container interior and through which the product         can be removed in a discharge direction that is perpendicular to         the opening; and     -   (B) a lid movable between (1) a closed position occluding the         opening, and (2) a fully opened position exposing the opening;         and wherein         -   (a) the peripheral wall includes a laterally inwardly             extending sealing member cantilevered over part of the             opening, the sealing member including a first portion and a             distal second portion extending from the first portion to             define a sealing surface that is generally parallel to the             discharge direction;         -   (b) the lid includes a closure flange that defines a             peripheral sealable surface which, when the lid is in the             closed position,             -   (i) is oriented generally parallel to the discharge                 direction,             -   (ii) is sealingly engaged with the sealing surface of                 the distal second portion of the sealing member of the                 peripheral wall so as to force the distal second portion                 laterally outwardly; and         -   (c) the largest lateral dimension of the sealing surface of             the peripheral wall sealing member distal second portion, as             measured perpendicular to the discharge direction and across             the locus defined by the sealing surface of the peripheral             wall of the sealing member distal second portion when the             lid is opened, is between about 0.3% and about 2.0% smaller             than the largest lateral dimension of the lid flange             sealable surface as measured across the locus of the flange             periphery defined by the lid flange sealable surface             whereby, when the lid is closed, the peripheral wall sealing             member distal second portion is forced laterally outwardly             by the lid flange sealable surface.

In embodiments that are presently most preferred, the largest lateral dimension of the sealing surface of the peripheral wall of the sealing member distal second portion is between about 0.50% and about 0.75% smaller than the largest lateral dimension of the lid flange sealable surface.

According to another aspect of the invention, another form of a closure system is provided for a container that has an interior where a product may be stored, and the closure system includes:

-   -   (A) a peripheral wall for extending from the container around an         opening to the container interior and through which the product         can be removed in a discharge direction that is perpendicular to         the opening; and     -   (B) a lid movable between (1) a closed position occluding the         opening, and (2) a fully opened position exposing the opening;         and wherein         -   (a) the peripheral wall has interior surface and further             includes a laterally inwardly extending sealing member             cantilevered from said interior surface over part of the             opening, the sealing member including a first portion and a             distal second portion extending from the first portion to             define a sealing surface that (i) is generally parallel to             the discharge direction, and (ii) has a height measured             along the discharge direction, and the ratio of the height             of said sealing surface to the largest lateral dimension of             said peripheral wall interior surface as measured             perpendicular to said discharge direction is between about             0.08 and about 0.17; and         -   (b) the lid includes a closure flange that defines a             peripheral sealable surface which, when the lid is in the             closed position, is             -   (i) oriented generally parallel to the discharge                 direction, and             -   (ii) sealingly engaged with the sealing surface of the                 distal second portion of the peripheral wall sealing                 member so as to force the distal second portion                 laterally outwardly.

The closure system of the present invention is especially suitable for (but not limited to) relatively large product discharge openings (e.g., an opening (which may be round, oval, or some other shape) wherein the minimum lateral dimension across the opening is at least 40 mm.).

Numerous other advantages and features of the present invention will become readily apparent from the following detailed description of the invention, from the claims, and from the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings forming part of the specification, in which like numerals are employed to designate like parts throughout the same,

FIG. 1 is a perspective view of a first embodiment of a closure system of the present invention as embodied in a closure for use on, or as part of, a container (not illustrated), and the closure is shown in a completely closed condition;

FIG. 2 is an enlarged, cross-sectional view taken generally along the plane 2-2 in FIG. 1;

FIG. 3 is an enlarged, fragmentary, cross-sectional view of the region in FIG. 2 indicated by the circle designated “FIG. 3”;

FIG. 4 is a perspective view of the first embodiment of the closure illustrated in FIG. 1, but in FIG. 4, the lid is shown in an open position;

FIG. 5 is an enlarged, cross-sectional view, taken generally along the plane 5-5 in FIG. 4;

FIG. 6 is an enlarged, fragmentary, cross-sectional view of the region in FIG. 5 indicated by the oval designated “FIG. 6;”

FIG. 7 is an enlarged, fragmentary cross-sectional view of the region in FIG. 5 indicated by the circle designated “FIG. 7;”

FIG. 8 is an enlarged, fragmentary view similar to FIG. 3, but FIG. 8 shows the lid just beginning to engage the body as the lid is closing;

FIG. 9 is a perspective view of a second embodiment of a closure system of the present invention as embodied in a closure for use on, or as part of, a container (not illustrated), and the closure is shown in a completely closed condition;

FIG. 10 is a top plan view of the second embodiment of the closure illustrated in FIG. 9;

FIG. 11 is a left side elevation view of the second embodiment of the closure illustrated in FIGS. 9 and 10;

FIG. 12 is an enlarged, cross-sectional view taken generally along the plane 12-12 in FIG. 10;

FIG. 13 is an enlarged, fragmentary, cross-sectional view of the region in FIG. 12 indicated by the circle designated “FIG. 13”;

FIG. 14 is a perspective view of the second embodiment of the closure illustrated in FIG. 9, but in FIG. 14, the lid is shown in an open position; and

FIG. 15 is an enlarged, cross-sectional view taken generally along the plane 15-15 in FIG. 14.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

While this invention is susceptible of embodiment in many different forms, this specification and the accompanying drawings disclose only some specific forms as examples of the invention. The invention is not intended to be limited to the embodiments so described, however. The scope of the invention is pointed out in the appended claims.

For ease of description, the closure system of this invention is described in a generally upright orientation that it could have at the upper end of a container when the container is positioned upright on its base. It will be understood, however, that the closure system of this invention may be manufactured, stored, transported, used, and sold in orientations other than the orientation described.

The closure system of this invention is suitable for use with a variety of conventional or special containers having various designs, the details of which, although not illustrated or described, would be apparent to those having skill in the art and an understanding of such containers. With respect to the broadest aspects of the invention, the container, per se, need not form part of the invention, and therefore, any particular container that is described herein is not intended to limit the broadest aspects of the invention.

One presently preferred, first embodiment of a closure system of the present invention is incorporated in the closure that is illustrated in FIGS. 1-8, and that is designated generally by reference number 30 in FIG. 1. The closure 30 is provided as a separately manufactured unit for mounting to the top of a container (not shown). It will be appreciated, however, that in some applications it may be desirable for the closure 30 to be formed as a unitary part, or extension, of the container wherein the unitary part or extension defines an upper end structure of the container, per se.

The container (not shown) may be a pouch-type structure or a more rigid structure. A substantially rigid, or slightly flexible-walled container typically has a conventional mouth which provides access to the container interior and product contained therein. The product may be a paste-like product or fluent product (which can be scooped or ladled from the container with a spoon, knife, ladle, etc.), or a product of small, individual items, such as nuts, candies, crackers, cookies, etc. (which can be scooped out of the container, ladled out of the container, or removed by hand from the container). Other contemplated products include ground coffee, sugar, or other material in the form of liquids, powders, gels, pastes, slurries, lotions, creams, etc. Such materials may be sold, for example, as a food product, a personal care product, an industrial or household product (such as lotions or creams), or other composition (e.g., for internal or external use by humans or animals, or for use in activities involving medicine, manufacturing, commercial or household maintenance, construction, agriculture, etc.).

A substantially rigid container or slightly flexible-walled container typically may have a neck or other suitable structure defining the container mouth having a cross-sectional configuration with which the closure 30 is adapted to engage. The body of the container may have another cross-sectional configuration that differs from the cross-sectional configuration of the container mouth. The container may, on the other hand, have a substantially uniform shape along its entire length or height without any neck portion of reduced size or different cross-section.

The container may also be a pouch or bag fabricated from a relatively thin, flexible film, or the container may be a squeezable container having a flexible wall or walls which can be grasped by the user and compressed somewhat. One embodiment of the closure 30 is especially suitable for use with a container that has substantially inflexible walls that are not intended to be squeezed inwardly by the user. Another embodiment is especially suitable for a flexible pouch-type container.

As shown in FIG. 4 for the first embodiment, the preferred structure of the closure 30 comprises (A) a peripheral wall 32 that defines the closure base or body 32, and (B) a lid 34 joined to the peripheral wall 32 (i.e., the closure base or body) by a hinge 36 which may be of any suitable conventional hinge design known in the closure art, or which may be of a special design, the details of which form no part of the present invention. In the embodiment illustrated in FIGS. 1-8, the hinge 36 incorporates the hinge design of the snap-action type disclosed in the U.S. Pat. No. 4,403,712. In the preferred, first embodiment illustrated in FIGS. 1-8, the closure peripheral wall 32 (i.e., the closure base or body), lid 34, and hinge 36 are molded from a suitable thermoplastic material (such as polypropylene or the like) as an integral structure (which may include a bi-injection molded feature or other multi-step injection molded features). Other materials may be employed instead.

In an alternate embodiment (not illustrated), the lid 34 could be a piece that is separate from the peripheral wall 32 (i.e., closure base or body), and that is not connected to the peripheral wall 32 by any hinge.

In yet another alternate embodiment (not illustrated), the lid 34 and peripheral wall 32 could be separate pieces that each has a cooperating portion of a hinge and that can be assembled together to provide a hinged assembly for accommodating pivoting movement of the lid 34 on the peripheral wall 32 between the closed and open positions.

In other contemplated embodiments, the peripheral wall 32 (or even the entire closure 30) need not be a structure or assembly that is completely separate from the container. Instead, the container could be made with a dispensing end structure that incorporates the closure 30, or at least the peripheral wall 32, as a unitary part of the top of the container. To create such an alternate embodiment, the illustrated first embodiment closure 30 could be modified so that it is formed as an extension of the top of the container, and the extending portion defining the closure peripheral wall 32 could then be characterized as a structural feature that functions to accommodate communication with the container interior. In any case, the peripheral wall 32 (whether it is a unitary portion of the top of the container or a separate piece that is releasably or permanently mounted at the top of the container) may be characterized as a peripheral wall for extending from the container around the opening to the container.

Regardless of whether or not the entire closure 30 (or just the peripheral wall 32) is molded as a unitary extension of a container or is a separate unit, the container may have an initially open bottom end opposite the top end on which the closure 30 is located, and such a bottom end could be used for accommodating the filling of the inverted container with the product. After the inverted container is filled with the product through the open bottom end of the container, the open bottom end of the container could be closed by suitable means, such as by a separate bottom end closure which could be attached to the container bottom end (e.g., through a suitable threaded engagement, snap-fit engagement, adhesive engagement, thermal bonding engagement, etc.). Alternatively, such an open bottom portion of the container could be deformed closed (e.g., with an appropriate process applying heat and force if the container bottom end portion is made from a thermoplastic material or other material that would accommodate the use of such a process).

Where the peripheral wall 32 is the base or body of a separate closure 30, as in the preferred, first embodiment illustrated in FIGS. 1-8, the peripheral wall 32 may have a skirt 40 (FIGS. 2 and 4) with a screw thread 42 (FIG. 2) for releasably attaching the base or body 32 to a mating thread of a container (not shown). Hereinafter in the description of the closure system, the peripheral wall 32 will be usually referred to simply as the closure base or body 32.

The closure body 32 and container could also be releasably connected by providing the body 32 with a conventional bead (not shown) for snap-fit engagement with a mating container groove (not shown), or by other means. Alternatively, the closure body 32 may be permanently attached to the container by means of induction bonding, ultrasonic bonding, gluing, or the like, depending upon the materials employed for the container and closure body 32.

The interior of the body 32 may also include special or conventional seal features to provide an enhanced leak-tight seal between the closure body 32 and the container. The illustrated body 32 employs such an enhanced seal feature in the form of a conventional “crab's claw” type of seal 44 (FIG. 2) for sealing against the container.

In the preferred first embodiment illustrated in FIGS. 1-8, the closure body 32 includes an upwardly projecting spout 50 (FIGS. 5 and 7) which has a cylindrical exterior surface 52 (FIG. 7) having an outside diameter D₁ (FIG. 7). The inside of the spout 50 is defined in part by an interior surface 54 (FIG. 7) which has a diameter D₂ and which has an annular, cylindrical configuration concentric with the spout exterior surface 52.

The closure body 32, and in particular the spout 50, defines a dispensing passage for communicating with the opening of the container (not shown) and defines a product discharge direction that is generally perpendicular to the container opening through which the product can be removed (by pouring, scooping, lifting out, etc.).

The closure body 32 includes a sealing member 60 (FIG. 7) which extends laterally inwardly from the spout interior surface 54 so that it is cantilevered over the container opening when the closure 30 is installed on the container. As can be seen in FIG. 7, the sealing member 60 includes a first portion 61 and a distal second portion 62 extending from the first portion 61. Preferably, the first portion 61 tapers so that it becomes thinner in the radially inward direction.

In the preferred embodiment, the exterior surface of the sealing member first portion 61 is defined by a circular radius R₁. The interior surface of the sealing member 60, extending along the sealing member first portion 61 as well as along the sealing member distal second portion 62, is defined by a circular radius R₂. The radius R₁ and the radius R₂ are located so that the arcuate surface defined by radius R₁ and the arcuate surface defined by the radius R₂ each becomes tangent to horizontal planes passing through the spout in an orientation perpendicular to the discharge direction. In particular, the arcuate surface defined by the radius R₁ is tangent to an upper plane P₁ (FIG. 7), and the arcuate surface defined by the radius R₂ is tangent to a lower plane P₂ (FIG. 7).

The maximum thickness of the sealing member 60 where it attaches to the spout 50 between the planes P₁ and P₂ is designated T₁ in FIG. 7. The sealing member exterior arcuate surface defined by the radius R₁ has a radially inwardly extending length designated L₁ in FIG. 7. The sealing member 60 extends radially inwardly from the spout interior surface 54 for a distance or length L₂ as designated in FIG. 7. The total height of the sealing member 60 is designated as H₁ in FIG. 7. The sealing member 60 projects below the point where the arcuate interior surface defined by the radius R₂ merges with the spout 50 (at the plane P₂), and the amount of this projection is shown in FIG. 7 as the distance H₂.

The sealing member distal second portion 62 has a radially inward end which, in the transverse cross-sectional configuration as illustrated in FIG. 7, is defined by (i) a laterally inwardly extending top arcuate surface 71, (ii) a laterally inwardly extending bottom arcuate surface 72, and (iii) a sealing surface 74 that is generally parallel to the discharge direction and that extends between, and merges with, the top arcuate surface 71 and bottom arcuate surface 72. The sealing surface 74 defines the most radially inwardly extent of the sealing member distal second portion, and the sealing surface 74 has a cylindrical or annular configuration having a diameter D₄ as illustrated in FIG. 7. The vertical height of the sealing surface 74, in the direction parallel to the discharge direction, is designated H₃ in FIG. 7. The sealing surface 74 is adapted to coact with a feature on the lid 34 when the lid 34 is closed as explained in detail hereinafter.

In the preferred configuration of the sealing member 60, the member 60 has a generally tapering configuration over a major portion of its length. The thinnest region occurs at the location where the distal second portion 62 is connected to the first portion 61, and the thinnest region dimension is designated T₂ in FIG. 7.

As can be seen in FIGS. 2 and 5, the closure body 32 includes a peripheral shoulder 80 for receiving the lid 34 when the lid 34 is closed. The lid 34 includes an outer frame or skirt 82 for confronting the closure body shoulder 80 when the lid 34 is closed. The frame or skirt 82 includes a radially inwardly extending annular portion 84 (FIGS. 2 and 6) which terminates in a circular opening 86. The opening 86 is covered by an insert disk 88 (FIGS. 2, 3, and 5) which is preferably bi-injection molded onto the annular portion 84. The disk 88 may be of the same material as the rest of the closure 30 or may be a different material. In one preferred embodiment, the disk 88 is a translucent material, and it may have a different tint or color than the rest of the closure. In other contemplated embodiments, a separate disk 88 need not be employed. Rather, the entire top of the lid 34 could be molded as one unitary structure together with the hinge 36 and body 32, and such a structure would not incorporate any bi-injection molded portions or features.

In order to hold the lid 34 in the closed position, the closure body 32 includes an upwardly projecting, annular flange 90. At the front of the closure body 32, the flange 90 includes an outwardly projecting engaging bead 92 for engaging a cooperating bead 94 on the inside of the closure lid skirt 82 at the front of the lid 34 (FIG. 5). As can be seen in FIG. 2, the front of the lid 34 has an outwardly projecting portion 96 for functioning as a finger or thumb lift to assist the user in lifting the lid.

With reference to FIGS. 5 and 6, the lid 34 includes a closure flange 100 which projects from the underside of the lid 34. The lid closure flange 100 defines a peripheral sealable surface 102 which is generally cylindrical and defines a diameter D₃ as illustrated in FIG. 6. The diameter D₃ of the lid sealable surface 102 is larger than the diameter D₄ of the closure body sealing member sealing the surface 74. The outer, distal edge of the flange 100 is tapered or chamfered at 104 as illustrated in FIG. 6. When the lid 34 is closed (FIGS. 2 and 3), the peripheral sealable surface 102 of the lid flange 100 is oriented generally parallel to the discharge direction and is sealingly engaged with the sealing surface 74 of the distal second portion 62 of the closure body peripheral wall sealing member 60 so as to force the distal second portion 62 laterally outwardly. FIG. 8 illustrates the lid 34 in an intermediate position as it is being closed on the closure body 32, and FIG. 8 shows how the closure lid flange 100 begins to engage the closure body sealing member 60 just prior to deforming the sealing member 60 radially outwardly.

To provide a robust closure system that withstands normal manufacturing and handling processes and that withstands normal use, especially in relatively large diameter closures, the diameter D₃ of the closure lid flange sealable surface 102 should be somewhat larger than the inner diameter of the closure body sealing member sealing surface 74 as measured in the as-molded, unstressed condition (diameter D₄ in FIG. 7). Specifically, in a preferred form of the invention, the largest lateral dimension of the sealing surface 74 of the sealing member distal second portion 62 (i.e., dimension D₄), as measured perpendicular to the discharge direction and across the locus defined by the sealing surface 74 of the sealing member distal second portion when the lid is opened, is between about 0.3% and about 2.0% smaller than the largest lateral dimension of the lid flange sealable surface 102 (i.e., dimension D₃) as measured across the locus of the periphery of the lid flange 100 defined by the lid flange sealable surface 102. A presently most preferred range of the largest lateral dimension of the sealing member sealing surface is between about 0.50% and about 0.75% smaller than the largest lateral dimension of the lid flange sealable surface 103. With such an interfering relationship, when the lid 34 is closed, the peripheral wall sealing member distal second portion 62 is forced laterally outwardly by the lid flange sealable surface 102 an amount sufficient to insure a good seal under normal conditions of use. This helps to provide a good seal without creating excessive fictional forces when the lid is closed and opened—thereby facilitating operation of the lid and also reducing wear on the sealing surfaces. In one presently preferred embodiment, the lid flange sealable surface 102 and the peripheral wall sealing member distal second portion 62 interfere when the lid 34 is in the closed position so as to force the peripheral wall sealing member distal second portion 62 radially outwardly a distance that is between about 0.05 mm. and about 0.51 mm., and that is preferably about 0.21 mm. or at least as great as about 0.20 mm.

A presently preferred range for the height H₃ (FIG. 7) of the sealing surface 74 is between about 0.10 mm. and about 1.02 mm. for round and oval closures. It is preferable to design the sealing surface 74 of the peripheral wall sealing member distal second portion so that it has a height H₃ (FIG. 7) based on a desired ratio of the sealing surface height H₃ to the distance L₂ (where L₂ is the laterally inward extension of the sealing member 60 from the spout interior surface 54). Such a desired ratio of H₃ to L₂ is between about 0.08 and about 0.17. This helps to provide a good seal without creating excessive fictional forces when the lid is closed and opened—thereby facilitating operation of the lid and also reducing wear on the sealing surfaces. In presently preferred embodiments identified in TABLE 1 discussed below, the sealing member distal second portion sealing surface 74 has a height (i.e., height H₃ in FIG. 7) between only about 0.15 mm. and about 0.35 mm.

In the illustrated embodiments, the peripheral wall sealing member distal second portion sealing surface 74 height H₃ (FIG. 7), as measured along the discharge direction, can be characterized as being between about 0.25% and about 0.38% of the largest lateral dimension D₄ (FIG. 7) as measured across the locus defined by the sealing surface 74 when the lid 34 is in the open condition. In the presently manufactured embodiments, the ratio H₃/D₄ (i.e., the ratio of the sealing member sealing surface height H₃ to the largest lateral dimension D₄ of the seal member sealing surface 74) is between about 0.002 and about 0.01 for round or oval closures.

Further, according to a preferred form of the invention, there is a preferred relationship between the interior surface 54 of the peripheral wall or spout 50 and the sealing surface 74 of the sealing member distal second portion 62. In particular, the peripheral wall interior surface 54 preferably has a maximum lateral dimension X (e.g., diameter D₂) defined as the largest lateral dimension defined by the peripheral wall interior surface 54 as measured perpendicular to the discharge direction, and the sealing surface 74 of the sealing member distal second portion 62 has a maximum lateral dimension Y (e.g., diameter D₄) defined as the largest lateral dimension measured across the locus defined by the sealing surface 74 measured perpendicular to the discharge direction, and the ratio of X to Y is between about 1.04 and about 1.08.

As can be seen in FIG. 3, when the lid 34 is closed, the lid flange sealable surface 102 extends inwardly in the direction opposite to the discharge direction, beyond the peripheral wall sealing member 60 by an amount designated S in FIG. 3. It has been found that some projection of the surface 62 beyond the deformed sealing member 60 is useful in insuring good operation of the seal between the lid flange 100 and the sealing member 60—especially for a closure 30 which has a relatively large discharge opening (e.g., 40 mm. or more) and which must accommodate creep or relaxation of the stressed closure material.

The extension S of the lid flange 100 below the sealing member 60 is also useful in circumstances wherein the interior pressure in the package can act to impose an outwardly directed force on the lid 34, including when the closed package is inverted. In a preferred design, the lid flange sealable surface 102 extends a distance 5 beyond the closure body sealing member 60 by an amount which is at least as great as 0.59% of the largest lateral dimension measured across the locus of the periphery defined by the lid flange sealable surface (i.e., dimension D₃ for the circular closure lid flange 100 illustrated in FIG. 3). In a presently preferred range, the extension distance S is between about 0.5% and about 10.0% of D₃ for a round closure (where D₃ is the diameter of the lid flange 100) or an oval closure (where D₃ for an oval closure is the length of the major axis). In presently manufactured closure system embodiments (which could be round or oval), the distance S is between about 0.60% and about 2.60% of the largest lateral dimension D₃ of the lid flange sealable surface 102. The extension distance S helps to provide a good seal without creating excessive frictional forces during opening and closing of the lid—thereby facilitating operation of the lid and also reducing wear on the sealing surfaces. In one preferred embodiment of a round closure wherein the closure body sealing member 60 has an inner diameter D₄ of at least 57 mm. (before the lid 34 is closed), the lid flange sealable surface 102 extends a distance S that is at least 1.40 mm. inwardly, in the direction opposite to the discharge direction beyond the peripheral wall sealing member 60 when the lid 34 is in the closed position.

In the above discussion of the dimensional relationships, the term “largest lateral dimension” has been employed with respect to a particular feature of interest. For the first embodiment illustrated in FIGS. 1-8, wherein the closure has a generally circular configuration, the “largest lateral dimension” is the diameter of the particular feature. In an oval or elliptical closure (such as the second embodiment discussed hereinafter), the “largest lateral dimension” would be the major axis of the oval or elliptical feature.

TABLE 1 below identifies two different sizes of a preferred embodiment of a round closure, closure A and closure B, and also identifies one embodiment of an oval closure C (discussed in detail following TABLE 1). TABLE 1 identifies various parameters and relationships for each round closure A and B, including those parameters and relationships discussed above, and identifies various parameters and relationships for the oval closure C as discussed in detail following TABLE 1. In TABLE 1, the numbers in column A (for closure A), column B (for closure B), and in column C (for oval closure C) are in millimeters, except for numbers in TABLE 1 that are followed by a percent sign. Numbers followed by a percent sign are the ratio of the parameters listed in the far left-hand column multiplied by 100. In TABLE 1, the listed values of the parameters are preferred values which have been found to provide the desired operation of the closure with respect to sealing and with respect to providing a structure with sufficient ruggedness or robustness to accommodate manufacturing tolerances, handling, and normal internal container pressures (including pressures applied to the closure lid from the product in an inverted container and/or from impacts upon the container). TABLE 1 C Parameters A B Major Axis Minor Axis H₁ 1.30 1.30 1.30 1.30 H₂ 0.80 0.80 0.79 0.79 L₁ 1.30 1.69 1.30 1.30 D₃ 57.70 74.02 80.62 48.87 S 1.50 1.44 0.48 0.48 S/D₃ 2.60% 1.95% 0.60% 0.98% D₄ 57.28 73.60 80.21 48.46 (D₃ − D₄)/2 0.21 0.21 0.205 0.205 (D₃ − D₄)/D₃ 0.73% 0.57% 0.51% 0.84% D₁ 62.55 79.78 86.36 54.61 D2 61.00 78.24 83.82 52.07 D₂/D₄ 1.065 1.063 1.045 1.074 L₂ = (D₂ − D₄)/2 1.86 2.32 1.805 1.805 L₂/D₃ 3.22% 3.13% 2.24% 3.69% L₂/D₂ 3.05% 2.97% 2.15% 3.47% L₂/D₃ 3.22% 3.13% 2.24% 3.69% T₂ 0.21 0.30 0.31 0.31 T₂/D₃ 0.36% 0.41% 0.38% 0.63% T₁ 0.50 0.50 0.51 0.51 R₁ 1.21 1.77 1.27 1.27 R₂ 1.21 1.77 1.22 1.22 R₁/D₃ 2.10% 2.39% 1.51% 2.50% H₃ 0.165 1.196 0.30 0.30 H₃/D₄ 029% 0.27% 0.37% 0.62% H₃/L₂ 0.089 0.085 0.166 0.166

A second embodiment of the present invention is illustrated in FIGS. 9-15 wherein an elliptical or oval closure 30A is shown. As can be seen in FIG. 14, the closure 30A includes a peripheral wall, base or body 32A for extending from a container (not shown) around an opening to the container interior and through which the product can be removed in a discharge direction that is perpendicular to the opening. The closure 30A also includes a lid 34A which is movable between (1) a closed position occluding the opening, and (2) a fully open position exposing the opening. In the preferred form of the second embodiment of the invention illustrated in FIGS. 9-15, the lid 34A is connected to the peripheral wall 32A by means of a floppy hinge 36A. The hinge 36A could be omitted altogether. Alternatively, the hinge 36A could be another type of hinge, such as a snap-action hinge.

The peripheral wall 32A includes a base flange 41A which extends laterally outwardly and which is adapted to be sealed to the wall of a container defining a discharge opening around which the flange 41A is mounted. The container could be generally rigid or flexible. The second embodiment of the closure 30A is especially suitable for use on a flexible container. The flexible container may be any suitable flexible container, including, but not limited to, a pouch-type container made from a thin, flexible, thermoplastic film. The flange 41A can be heat-sealed or secured with adhesive to the wall of the container. Other attachment systems may be employed, including purely mechanical attachment systems.

In the preferred form of the second embodiment 30A illustrated in FIG. 14, the peripheral wall 32A is initially molded first, and then the closure lid 34A is bi-injection molded to the peripheral wall 32A. Preferably, if the closure 30A includes a floppy-type hinge 36A illustrated in FIG. 14, a lower portion of the hinge 36A is initially molded as a unitary extension of the peripheral wall 32A, and an upper part of the hinge is molded as a unitary extension of the lid 34A. The two hinge extensions are connected together outwardly of the hinge fold line when the lid 34A is bi-injection molded onto the peripheral wall 32A.

As can be seen in FIG. 12, the lid 34A preferably includes a downwardly extending latch tab 37A for being received in a snap-fit type engaging slot 39A in the peripheral wall 32A. The snap-fit engagement can be overcome when sufficient force is applied by the user's finger or thumb to the lid 34A in an upward direction to lift the lid 34A away from the peripheral wall 32A.

As can be seen in FIGS. 12 and 14, the peripheral wall 32A includes a sealing member 60A. In cross section, the undeformed, as-molded configuration of the sealing member 60A and of the lid flange 100A is identical with the configuration of the sealing member 60 and lid flange 100, respectively, as described above in detail for the first embodiment of the closure illustrated in FIGS. 1-8.

In the second embodiment closure, the lid 34A includes an outwardly projecting flange 100A. The flange 100A is adapted to be sealed by the sealing member 60A when the lid 34A is closed on the peripheral wall 32A as illustrated in FIG. 13. The sealing member 60A includes a sealing surface 74A that has an overall oval configuration and that is flat as viewed in cross section in FIG. 13 so that it is generally parallel to the product discharge direction. The surface 74A is adapted for sealing against a peripheral sealable surface 102A on the exterior of the lid flange 100A.

In this second embodiment of the closure 34A illustrated in FIGS. 9-15, the sealing member 60A has an oval configuration, and the lid sealable flange 100A has a cooperating oval configuration. The major axis of the oval configuration of a particular feature of the closure 30A may be characterized as the “largest lateral dimension” of that particular feature. The various lateral dimensions of the features of the closure sealing member 60A and lid flange 100A may be conveniently designated by the same dimensional signifiers used for illustrating the first embodiment of the closure 30 in FIGS. 3 and 7. That is, the various dimensions such as D₁, D₂, D₃, D₄, L₁, L₂, H₁, H₂, H₃, T₁, T₂, etc. in the first embodiment apply also to the configuration of the oval closure illustrated in FIGS. 9-15. To the extent that the oval closure features have a major and minor axis, such major and minor axes are listed in TABLE 1 in column C for the embodiment illustrated in FIGS. 9-15. The values listed in the “Major Axis” column and “Minor Axis” under heading C in TABLE 1 are preferred values which have been found to provide the desired operation of the closure with respect to sealing and with respect to providing a structure with sufficient ruggedness or robustness to accommodate manufacturing tolerances, handling, and normal internal container pressures (including pressures applied to the closure lid from the product in an inverted container and/or from impacts upon the container).

With respect to either the round, first embodiment illustrated in FIGS. 1-8 or the oval, second embodiment illustrated in FIGS. 1-15, it has been found that the top arcuate surface 71, 71A, and bottom arcuate surface 72, 72A, function to facilitate the closing and opening engagement of the closure lid sealable flange 100, 100A with the peripheral wall sealing member 60, 60A, and that these arcuate surfaces 71, 71A, 72, 72A further eliminate sharp corner edges that a user might find objectionable when contacted by the user's fingers.

Also, with respect to all of the embodiments, the configuration and size relationships of the cooperating structures contribute to providing an arrangement in which the lid sealable flange 100, 100A is properly guided during closing of the lid 34, 34A so as to facilitate proper closing and sealing, especially for “wide mouth” sizes (e.g., 40 mm. or greater). The arrangement also is sufficiently robust to accommodate some warpage or other distortion—as well as normal handling during manufacturing, shipping and use—without deleterious effects on the sealing capability.

It will be readily apparent from the foregoing detailed description of the invention and from the illustrations thereof that numerous variations and modifications may be effected without departing from the true spirit and scope of the novel concepts or principles of this invention. 

1. A closure system for a container that has an interior where a product may be stored, said closure system comprising: (A) a peripheral wall for extending from said container around an opening to the container interior and through which the product can be removed in a discharge direction that is perpendicular to said opening; and (B) a lid movable between (1) a closed position occluding said opening, and (2) a fully opened position exposing said opening; and wherein (a) said peripheral wall includes a laterally inwardly extending sealing member cantilevered over part of said opening, said sealing member including a tapering first portion that becomes thinner in the radially inward direction, said tapering first portion being defined by an outwardly convex first surface and an inwardly concave second surface, said sealing member including a distal second portion extending from said first portion, said distal second portion having a transverse cross-sectional configuration that is defined by (i) a laterally inwardly extending top arcuate surface, (ii) a laterally inwardly extending bottom arcuate surface, and (iii) a sealing surface that is generally parallel to said discharge direction and that extends between, and merges with, said top arcuate surface and said bottom arcuate surface; and (b) said lid includes a closure flange that defines a peripheral sealable surface which, when said lid is in said closed position, is (i) oriented generally parallel to said discharge direction, and (ii) sealingly engaged with said sealing surface of said distal second portion of said peripheral wall sealing member so as to force said distal second portion laterally outwardly, and in which: (iii) when said lid is in said closed position, said lid flange sealable surface extends inwardly, in the direction opposite to said discharge direction, beyond said peripheral wall sealing member by an amount at least as great as 0.59% of the largest lateral dimension measured across the locus of the periphery defined by said lid flange sealable surface; (iv) the largest lateral dimension of said sealing surface of said sealing member distal second portion, as measured perpendicular to said discharge direction and across the locus defined by said sealing surface of said sealing member distal second portion when said lid is opened, is between about 0.3% and about 2.0% smaller than the largest lateral dimension of said lid flange sealable surface as measured across the locus of the flange periphery defined by said lid flange sealable surface whereby, when said lid is closed, said peripheral wall sealing member distal second portion is forced laterally outwardly by said lid flange sealable surface; (v) said peripheral wall has an interior surface from which said sealing member extends, and wherein said peripheral wall interior surface has a dimension X defined as the largest lateral dimension across the locus defined by said peripheral wall interior surface as measured perpendicular to said discharge direction; wherein said sealing surface of said sealing member distal second portion has a dimension Y defined as the largest lateral dimension measured across the locus defined by said sealing surface of said sealing member distal second portion as measured perpendicular to the discharge direction; and wherein the ratio of X to Y is between about 1.04 and about 1.08; and (vi) said peripheral wall sealing member distal second portion sealing surface has a height as measured along said discharge direction, and the ratio of said sealing surface height to said peripheral wall interior surface dimension X is between about 0.08 and about 0.17.
 2. A closure system for a container that has an interior where a product may be stored, said closure system comprising: (A) a peripheral wall for extending from said container around an opening to the container interior and through which the product can be removed in a discharge direction that is perpendicular to said opening; and (B) a lid movable between (1) a closed position occluding said opening, and (2) a fully opened position exposing said opening; and wherein (a) said peripheral wall includes a laterally inwardly extending sealing member cantilevered over part of said opening, said sealing member including a first portion and a distal second portion having a transverse cross-sectional configuration that is defined by (i) a laterally inwardly extending top arcuate surface, (ii) a laterally inwardly extending bottom arcuate surface, and (iii) a sealing surface that is generally parallel to said discharge direction and that extends between, and merges with, said top arcuate surface and said bottom arcuate surface; and (b) said lid includes a closure flange that defines a peripheral sealable surface which, when said lid is in said closed position, is (i) oriented generally parallel to said discharge direction, and (ii) sealingly engaged with said sealing surface of said distal second portion of said peripheral wall sealing member so as to force said distal second portion laterally outwardly.
 3. The system in accordance with claim 2 in which said system is a closure that is separate from, but attachable to, a container that has an opening to the container interior; said closure includes a body defining said peripheral wall; and said lid and body are molded as an unitary structure joined by a hinge.
 4. The system in accordance with claim 2 in which said lid flange and said peripheral wall sealing member each has an oval configuration.
 5. The system in accordance with claim 2 in which, when said lid is in said closed position, said lid flange sealable surface extends inwardly, in the direction opposite to said discharge direction, beyond said peripheral wall sealing member by an amount that is between about 0.5% and 10.0% of the largest lateral dimension measured across the locus of the periphery defined by said lid flange sealable surface.
 6. The system in accordance with claim 2 in which the largest lateral dimension of said sealing surface of said peripheral wall sealing member distal second portion, as measured perpendicular to said discharge direction and across the locus defined by said sealing surface of said peripheral wall sealing member distal second portion when said lid is opened, is between about 0.3% and about 2.0% smaller than the largest lateral dimension of said lid flange sealable surface as measured across the locus of the flange periphery defined by said lid flange sealable surface whereby, when said lid is closed, said peripheral wall sealing member distal second portion is forced laterally outwardly by said lid flange sealable surface.
 7. The system in accordance with claim 2 in which said lid flange sealable surface and said peripheral wall sealing member distal second portion interfere when said lid is in said closed position so as to force said peripheral wall sealing member distal second portion laterally outwardly a distance at least as great as about 0.2 mm.
 8. The system in accordance with claim 2 in which said peripheral wall has an interior surface from which said sealing member extends; and said peripheral wall sealing member distal second portion sealing surface has a height, as measured along said discharge direction, and the ratio of said sealing surface height to the largest lateral dimension across the locus defined by said peripheral wall interior surface as measured perpendicular to said discharge direction is between about 0.08 and about 0.17.
 9. The system in accordance with claim 8 in which said sealing surface height is between about 0.10 mm. and about 1.02 mm.
 10. The system in accordance with claim 2 in which said peripheral wall has an interior surface from which said sealing member extends; and wherein said peripheral wall interior surface has a dimension X defined as the largest lateral dimension across the locus defined by said peripheral wall interior surface as measured perpendicular to said discharge direction; wherein said sealing surface of said sealing member distal second portion has a dimension Y defined as the largest lateral dimension measured across the locus defined by said sealing surface of said sealing member distal second portion as measured perpendicular to the discharge direction; and wherein the ratio of X to Y is between about 1.04 and about 1.08.
 11. The system in accordance with claim 2 in which said sealing member first portion tapers and becomes thinner in the radially inward direction; and said sealing member first portion is defined by an outwardly convex first surface and an inwardly concave second surface.
 12. A closure system for a container that has an interior where a product may be stored, said closure system comprising: (A) a peripheral wall for extending from said container around an opening to the container interior and through which the product can be removed in a discharge direction that is perpendicular to said opening; and (B) a lid movable between (1) a closed position occluding said opening, and (2) a fully opened position exposing said opening; and wherein (a) said peripheral wall includes a laterally inwardly extending sealing member cantilevered over part of said opening, said sealing member including a first portion and a distal second portion extending from said first portion to define a sealing surface that is generally parallel to said discharge direction; and (b) said lid includes a closure flange that defines a peripheral sealable surface which, when said lid is in said closed position, (i) is oriented generally parallel to said discharge direction, (ii) has a minimum lateral dimension measured across the locus of the periphery defined by the sealable surface that exceeds 40 mm.; (iii) is sealingly engaged with said sealing surface of said distal second portion of said sealing member of said peripheral wall so as to force said distal second portion laterally outwardly; and (iv) extends inwardly, in the direction opposite to said discharge direction, beyond said peripheral wall sealing member by an amount that is between about 0.5% and about 10.0% of the largest lateral dimension measured across the locus of the periphery defined by said lid flange sealable surface.
 13. The system in accordance with claim 12 in which said system is a closure that is separate from, but attachable to, a container that has an opening to the container interior; said closure includes a body defining said peripheral wall; and said lid and body are molded as an unitary structure joined by a hinge.
 14. The system in accordance with claim 12 in which (1) the largest lateral dimension of said sealing surface of said sealing member distal second portion, as measured perpendicular to said discharge direction and across the locus defined by said sealing surface of said sealing member distal second portion when said lid is opened, is between about 0.3% and about 2.0% smaller than the largest lateral dimension of said lid flange sealable surface as measured across the locus of the flange periphery defined by said lid flange sealable surface whereby, when said lid is closed, said peripheral wall sealing member distal second portion is forced laterally outwardly by said lid flange sealable surface; (2) said peripheral wall has an interior surface from which said sealing member extends, and wherein said peripheral wall interior surface has a dimension X defined as the largest lateral dimension across the locus defined by said peripheral wall interior surface as measured perpendicular to said discharge direction; wherein said sealing surface of said sealing member distal second portion has a dimension Y defined as the largest lateral dimension measured across the locus defined by said sealing surface of said sealing member distal second portion as measured perpendicular to the discharge direction; and wherein the ratio of X to Y is between about 1.04 and about 1.08; (3) said peripheral wall sealing member distal second portion sealing surface has a height as measured along said discharge direction, and the ratio of said sealing surface height to said peripheral wall interior surface dimension X is between about 0.08 and about 0.17; (4) said sealing member first portion tapers and becomes thinner in the radially inward direction; and (5) said sealing member first portion is defined by an outwardly convex first surface and an inwardly concave second surface.
 15. A closure system for a container that has an interior where a product may be stored, said closure system comprising: (A) a peripheral wall for extending from said container around an opening to the container interior and through which the product can be removed in a discharge direction that is perpendicular to said opening; and (B) a lid movable between (1) a closed position occluding said opening, and (2) a fully opened position exposing said opening; and wherein (a) said peripheral wall includes a laterally inwardly extending sealing member cantilevered over part of said opening, said sealing member including a first portion and a distal second portion extending from said first portion to define a sealing surface that is generally parallel to said discharge direction; (b) said lid includes a closure flange that defines a peripheral sealable surface which, when said lid is in said closed position, (i) is oriented generally parallel to said discharge direction, (ii) is sealingly engaged with said sealing surface of said distal second portion of said sealing member of said peripheral wall so as to force said distal second portion laterally outwardly; and (c) the largest lateral dimension of said sealing surface of said peripheral wall sealing member distal second portion, as measured perpendicular to said discharge direction and across the locus defined by said sealing surface of said peripheral wall of said sealing member distal second portion when said lid is opened, is between about 0.3% and about 2.0% smaller than the largest lateral dimension of said lid flange sealable surface as measured across the locus of the flange periphery defined by said lid flange sealable surface whereby, when said lid is closed, said peripheral wall sealing member distal second portion is forced laterally outwardly by said lid flange sealable surface.
 16. The system in accordance with claim 15 in which said system is a closure that is separate from, but attachable to, a container that has an opening to the container interior; said closure includes a body defining said peripheral wall; and said lid and body are molded as an unitary structure joined by a hinge.
 17. The system in accordance with claim 15 in which (1) when said lid is in said closed position, said flange sealable surface extends inwardly, in the direction opposite to said discharge direction, beyond said peripheral wall sealing member by an amount that is between about 0.5% and about 10.0% of the largest lateral dimension measured across the locus of the periphery defined by said lid flange sealable surface; (2) said peripheral wall has an interior surface from which said sealing member extends, and wherein said peripheral wall interior surface has a dimension X defined as the largest lateral dimension across the locus defined by said peripheral wall interior surface as measured perpendicular to said discharge direction; wherein said sealing surface of said sealing member distal second portion has a dimension Y defined as the largest lateral dimension measured across the locus defined by said sealing surface of said sealing member distal second portion as measured perpendicular to the discharge direction; and wherein the ratio of X to Y is between about 1.04 and about 1.08; (3) said peripheral wall sealing member distal second portion sealing surface has a height as measured along said discharge direction, and the ratio of said sealing surface height to said peripheral wall interior surface dimension X is between about 0.08 an 0.17; (4) said sealing member first portion tapers and becomes thinner in the radially inward direction; and (5) said sealing member first portion is defined by an outwardly convex first surface and an inwardly concave second surface.
 18. A closure system for a container that has an interior where a product may be stored, said closure system comprising: (A) a peripheral wall for extending from said container around an opening to the container interior and through which the product can be removed in a discharge direction that is perpendicular to said opening; and (B) a lid movable between (1) a closed position occluding said opening, and (2) a fully opened position exposing said opening; and wherein (a) said peripheral wall has an interior surface and further includes a laterally inwardly extending sealing member cantilevered from said interior surface over part of said opening, said sealing member including a first portion and a distal second portion extending from said first portion to define a sealing surface that (i) is generally parallel to said discharge direction, and (ii) has a height as measured along said discharge direction, and the ratio of the height of said sealing surface to the largest lateral dimension of said peripheral wall interior surface as measured perpendicular to said discharge direction is between about 0.08 and about 0.17; and (b) said lid includes a closure flange that defines a peripheral sealable surface which, when said lid is in said closed position, is (i) oriented generally parallel to said discharge direction, and (ii) sealingly engaged with said sealing surface of said distal second portion of said peripheral wall sealing member so as to force said distal second portion laterally outwardly.
 19. The system in accordance with claim 18 in which said system is a closure that is separate from, but attachable to, a container that has an opening to the container interior; said closure includes a body defining said peripheral wall; and said lid and body are molded as an unitary structure joined by a hinge.
 20. The system in accordance with claim 18 in which, (1) when said lid is in said closed position, said lid flange sealable surface extends inwardly, in the direction opposite to said discharge direction, beyond said peripheral wall sealing member by an amount that is between about 0.5% and about 10.0% of the largest lateral dimension measured across the locus of the periphery defined by said lid flange sealable surface; (2) the largest lateral dimension of said sealing surface of said peripheral wall sealing member distal second portion, as measured perpendicular to said discharge direction and across the locus defined by said sealing surface of said peripheral wall sealing member distal second portion when said lid is opened, is between about 0.3% and about 2.0% smaller than the largest lateral dimension of said lid flange sealable surface as measured across the locus of the flange periphery defined by said lid flange sealable surface whereby, when said lid is closed, said peripheral wall sealing member distal second portion is forced laterally outwardly by said lid flange sealable surface; (3) said peripheral wall has an interior surface from which said sealing member extends, and wherein said peripheral wall interior surface has a dimension X defined as the largest lateral dimension across the locus defined by said peripheral wall interior surface as measured perpendicular to said discharge direction; wherein said sealing surface of said sealing member distal second portion has a dimension Y defined as the largest lateral dimension measured across the locus defined by said sealing surface of said sealing member distal second portion as measured perpendicular to the discharge direction; wherein the ratio of X to Y is between about 1.04 and about 1.08; (4) said sealing member first portion tapers and becomes thinner in the radially inward direction; (5) said sealing member first portion is defined by an outwardly convex first surface and an inwardly concave second surface, and (6) said sealing surface height is between about 0.10 mm. and about 1.02 mm. 